1. Field of the Invention
The present invention relates to an endoscope including an insertion section configured to be inserted into body cavities.
2. Description of the Related Art
At a distal direction side part of an insertion section of any endoscope, a distal rigid section is provided. The distal rigid section includes a distal rigid section main body, and a functional section such as an imaging unit. The distal rigid section main body is provided with an inner peripheral surface which defines a space accommodating the functional section, and which is extended along longitudinal directions. The functional section is secured to the inner peripheral surface of the distal rigid section main body, with adhesive, screws or the like.
Jpn. Pat. Appln. KOKAI Publication No. 2003-260029 discloses an endoscope in which an imaging unit, i.e., functional section, is fixed in a distal rigid section main body with screws and filler. In this endoscope, the distal rigid section main body is made of electrically insulating material such as resin or ceramics, and an outer peripheral surface of the distal rigid section main body is electrically insulated from the imaging unit. Hence, if the endoscope is used with a high-frequency instrument, the electric current used in high-frequency treatment is prevented from flowing to the endoscope.